a. Field of the Invention
My invention concerns the display of information from multiple sources, in a way that permits rapid assimilation and interpretation of the information. In particular, my invention concerns the display of information from the inspection of a work piece and more specifically, the display of information from the remote inspection of the work piece.
b. Related Art
Various systems or parts must be inspected periodically or when a problem is suspected. For example, aircraft engines have a series of turbines, each having a number of turbine blades, which must be inspected from time to time. As shown in FIG. 1b, if, for example, an aircraft engine ingests a bird, a crack 110 in a turbine blade 106 may develop. The crack 110 may be either (a) insignificant such that no maintenance is needed, (b) relatively small such that the crack may be ground out to form a "blend" (i.e., an aerodynamically acceptable shaping), or (c) relatively large such that the blade 106 must be replaced.
As shown in the simplified schematic of FIG. 1a, turbine blades 106, which extend radially from an axis 104, are confined within a housing 102. To facilitate inspection of the turbine blades 106 without opening the housing 102, one or more inspection ports 108 are provided. Remote visual inspection systems, including optical instruments such as borescopes, flexible fiberscopes, and flexible videoimagescopes for example, are often used to remotely inspect the turbine blades 106. More specifically, each of the aforementioned optical instruments includes an insertion tube that may be inserted through the inspection port 108. In each case, the insertion tube relays an image, received at its distal end, which is within the housing 102, to its proximal end, which is outside of the housing 102. An electronic turning tool (such as model OTT, sold by Olympus America Inc.) may be used to automatically and precisely rotate the turbine such that each blade 106 may be viewed and such that blades 106 of interest may be "tagged" for later, more thorough, inspection. Although borescopes, flexible fiberscopes, and flexible videoimagescopes are known to those skilled in the art, a brief overview of these optical instruments is provided below for the reader's convenience.
FIG. 2a illustrates a side view of a rigid borescope 200 which may be used, in conjunction with an attached video camera (not shown), as a video source for the display system of my invention. As shown in FIG. 2a, the borescope includes a body 202, which may include a handle 203 for example, and an insertion tube 204. The body 202 is connected to the proximal end of the insertion tube 204. At the distal end of the insertion tube, a tip adapter 211 includes a lens system 206 having a field-of-view 208, and a light emitting means 210. Although the tip adapter 211 shown provides 90 degree (or right angle) viewing, other tip adapters (e.g., direct view, fore oblique 45 degree, and retro 110 degree) are available, as is known to those skilled in the art.
The body 202 of the borescope includes a focus control ring 214 and an eyepiece 212. The borescope may also include a orbital scan dial 216 which permits a user to rotate (e.g., through 370 degrees) the insertion tube 204 with respect to the body 202. The orbital scan dial 216 preferably includes a orbital scan direction indicator 218 such that a user can determine the orientation of the tip adapter 211 when it is shielded from the view of the user, for example, by the housing 102. The body 202 also preferably includes a light guide connector 220 for accepting illumination light from an external light source.
An eyecup 222 is provided to protect the eyepiece 212 optics when the borescope 200 is not in use. A video adapter 224 may be used to connect a video camera (not shown) to the eyepiece 212 such that inspection via a video monitor is possible. The video camera outputs video frames which comply with the National Television Standards Committee (or "NTSC"), the Phase Alternating Line system (or "PAL"), or the S video (or Y-C) standard, for example.
FIG. 2b is a cross-sectional side view of a portion of the insertion tube 204 of the rigid borescope 200 of FIG. 2a. As shown, wall 228 forms an outer cylinder which surrounds wall 230 forming an inner cylinder. The space defined within the inner cylinder houses an objective lens 206' and an optical system 226 which relays the image from the objective lens 206' to the eyepiece 212. A cavity 232 formed between the inner and outer cylinders may be used to accommodate light guides, such as fiber optic strands for example. A working channel (not shown) may also be provided, through which sensors and/or tools may be provided.
FIG. 2c is an end view of the distal end of a direct view optical tip adapter 211'. As shown in FIG. 2c, a window 210', for passing light from the light guides to illuminate the work piece being inspected, may be provided around the objective lens 206'.
FIG. 3a is a side view of a flexible fiberscope 300 which may be used, in conjunction with an attached video camera (not shown), as a video source for the display system of my invention. As with the rigid borescope 200 discussed above, the flexible fiberscope 300 also includes a body 302 and an insertion tube 304. However, in this instance, the insertion tube 304 is flexible such that its distal end may be articulated left and right, by means of left-right articulation control 310, and up and down, by means of up-down articulation control 314. The left-right articulation control 310 may be locked by brake 312, while the up-down articulation control 314 may be locked by brake 316. The body 302 also includes a diopter adjusting ring 306 and an eyepiece 308. As was the case with the rigid borescope 200 discussed above, the eyepiece may by covered with an eye cup 350 when not in use. Further, an adapter 320 may be used to connect a video camera (not shown) to the eyepiece 308. Finally, a light guide connector 318 permits connection to an external light source.
FIG. 3b is a cross-sectional side view, and FIG. 3c is an end view of the distal end, of the insertion tube 304 of the flexible fiberscope 300 of FIG. 3a. Wall 322 defines an outer cylinder and wall 340 defines an inner cylinder. Within the space 324 defined by the inner cylinder, a bundle of optical fibers 330 carries an image focused at its distal end by objective lens 332. Light guide and working channels 326 and 328, located between the inner and outer cylinders, may for example house an illumination means and may accommodate sensors and/or tools.
FIG. 4a is a side view of a flexible videoimagescope 400 which may be used as a video source for the display system of my invention. As with the flexible fiberscope 300 discussed above, the flexible videoimagescope 400 also includes a body 402 and a flexible insertion tube 404. The distal end of the flexible insertion tube 404 may be articulated left and right, by means of left-right articulation control 408, and up and down, by means of up-down articulation control 412. The left-right articulation control 408 may be locked by brake 410, while the up-down articulation control 412 may be locked by brake 414. Finally, a light guide and video cable 418 permits connection to an external light source, via connector 420, and to a camera control unit, via connector 422.
Unlike the rigid borescope 200 and the flexible fiberscope 300 discussed above, the videoimagescope 400 does not have focus or diopter adjustment rings, nor does it have an eyepiece. This is because, as alluded to above, the videoimagescope provides a video output to an external camera control unit. More specifically, as shown in FIG. 4b, which is a partial cut-away, perspective view of the distal end of the videoimagescope of FIG. 4a, an objective lens 450 focuses an image 458' of an object 458 in its field of view 456, onto an imaging device, such as a charge coupled device (or "CCD") 452 for example. The CCD 452 (and associated circuitry) provides a sequence of analog waveforms based on the charge accumulated in each element of the CCD array. The camera control unit, mentioned above, converts the sequence of analog waveforms to frames of video, which comply with the NTSC, PAL or S video standard for example.
As is further shown in the perspective view of FIG. 4b, the distal end of the insertion tube of the videoimagescope 400 includes an illumination window 432 passing light from a light guide 430, as well as a working channel 440 terminating at port 442.
To reiterate, each of the above mentioned optical instruments may include a working channel through which a grinding tool, or retrieval tool (e.g., a magnet, a snare loop, a four-wire basket, or forceps) may pass. Moreover, a sensor, such as an eddy probe or ultrasound sensor (See e.g., ultrasound sensor 600 of FIG. 6) for example, may pass through the working channel. Such probes or sensors are useful for confirming an interpretation of video data. For example, an inspector inspecting a turbine blade may observe a dark section which may be a crack, or merely a shadow. Eddy current or ultrasound sensor output may be used to determine whether the dark section is in fact a crack, or merely a shadow.
Combining video data with sensor data is known. For example, in the medical field, the use of an endoscopic ultrasound center (e.g. model EU-M30 manufactured by Olympus Optical Co., Ltd.) with a videoscope (e.g., an EVIS Series videoscope manufactured by Olympus Optical Co., Ltd) and a video processing center (e.g., an EVIS Video System Center manufactured by Olympus Optical Co., Ltd.) to provide a picture-in-picture display of the videoscope image within the ultrasound image is known. Also, U.S. Pat. No. 4,855,820 (hereinafter referred to as "the Barbour patent") discusses a video display system in which the readout of a temperature sensor is displayed over the video output of a video camera. Unfortunately, in each of these known systems, the data from the sensor is displayed at an arbitrary location, without regard to the location of the sensor. Consequently, the operator must switch his or her attention between the video displaying the actual sensor (e.g., to move the sensor with respect to the observed object) and viewing the output data of the sensor. Moreover, in the Barbour patent, the sensor output is a digital readout, i.e., a number. For rapidly changing data, such a readout is not practical because it is difficult to quickly assimilate and interpret.
U.S. Pat. No. 4,642,687 (hereinafter referred to as "the Wedgwood et al patent") discusses a system for detecting non-visual signals, such as those based on ultrasound or radiation for example. The system discussed in the Wedgwood et al patent includes (i) a movable probe which indicates the location of a detection system and includes a light source which is "on" when detection is positive, (ii) a video camera which responds to the light source, (iii) a memory system which stores image locations at which the light source was "on", and (iv) a mixer for creating a superimposed image based on the output of the memory system and the output of the video camera. Unfortunately, whether or not the camera recognizes the probe depends on the on/off state of the detector. Moreover, storage and readout of the image locations from memory would apparently have to be synchronized with the video output of the video camera--indeed, not a trivial task!
Thus, a display system in which sensor data can be easily and rapidly viewed, assimilated, and interpreted, in conjunction with associated video, is needed. Such a display system should be operable with remote visual inspection systems including optical instruments such as borescopes, fiberscopes, and videoimagescopes for example. Finally, the system should permit generation of a graphical profile of the work piece being inspected.